Kosher meals conform to Jewish dietary laws. While there are varying degrees of strictness of observance among Jews, kosher meals include only those foods that are permissible for consumption and only in the various combinations permitted under Jewish law. One of the best-known kosher dietary laws is the requirement that Jews consume dairy and meat products at different times, never combining the two in a single meal. As a result, kosher restaurants, as opposed to restaurants that offer non-kosher Jewish ethnic food, typically specialize in either dairy- or meat-based meals.
The religious dietary laws of Judaism are very precise, and there are occasionally disagreements between rabbis as to which foods and eating practices are permissible. There are several different types of food that are simply not permitted under kosher rules. For example, meat from pigs, rabbits, and reptiles is not kosher in any form. Meat from other animals, such as cows, is permissible, however, and not every part of permissible animals is kosher for consumption. In addition, there are rules for the appropriate way to butcher these animals that must be followed in order for their meat to be considered suitable for kosher meals.
In very observant households, the content of kosher meals is strictly enforced so as to prevent dairy and meat from being served together at the same meal. Some households will also refuse to serve fish and meat at the same meal. In such households, menus are planned so that some meals feature milk products while others contain meat and poultry. Other foods such as fruits and vegetables can be served with either dairy or meat. In these households, separate sets of dishes are used to serve each type of meal.
The suitability of many modern, processed foods for kosher meals is of great concern to observant Jews because many food stabilizers, additives, and flavorings may have their origins in either nonkosher meats or dairy products, which could compromise the integrity of the kosher meals in which they are used. For this reason, many food manufacturers now voluntarily submit to a kosher certification process so that they can market their products to those who observe kosher laws. This process allows a rabbi to supervise the manufacturing process of these foods so that he can assure observant Jews that the food is kosher and can also direct purchasers of the food as to whether the product is suitable for meat meals, dairy meals, or both.